“Tradicional” analysis.

Fourier amplitude of geopotential height

Fourier amplitude of geopotential height

Wave 3 component of the geopotential field of each season at 200hPa.

Wave 3 component of the geopotential field of each season at 200hPa.

Mean wave 3 component of geopotential height between 65°S and 35°S

Mean wave 3 component of geopotential height between 65°S and 35°S

Now this has some problems… yada yada yada, alternative analysis.

New seasons

First 4 EOFs derived from the 200hPa geopotential zonal anomaly field between 30°S and 80°S with zonal wave 1 filtered out.

First 4 EOFs derived from the 200hPa geopotential zonal anomaly field between 30°S and 80°S with zonal wave 1 filtered out.

Fourier decomposition by latitude of each EOF.

Fourier decomposition by latitude of each EOF.

PC1 to PC4 represent the principal modes of variability of the geopotential field with wavenumber greater than 1…

PC1 and PC2 both are dominated by a wave 3 pattern. They both explain an almost equal proportion of the total variance and represent a wave 3 pattern offset by 1/4 wavelength. From that, one can infer that they are degenerated modes that represent the same wave pattern and it’s meridional movement. PC3 is mainly a hemispheric scale wave 2 with a small contribution of wave 4 north of 45°S. PC4 exhibits a more complex pattern with both waves 2 and 3 contributing to the field. The result is a wave 3-ish pattern on the eastern hemisphere that affects the Atlantic and the Indian oceans but disappears over the central-south Pacific.

This result suggest that the ZW3 could be represented by a linear combination of PC1 and PC2 at the same time preserving it’s meridional propagation and zonal variation.

Monthly mean values for each PC. Colors and shapes divide months into 5 'seasons'.

Monthly mean values for each PC. Colors and shapes divide months into 5 ‘seasons’.

NO VA. Clústering jerárquico. Cortando en ~0.03 se obtienen 4 clusters, y un 5to separando Abril de ASO por continuidad temporal. Confirma la validez del agrupamiento "a ojo"

NO VA. Clústering jerárquico. Cortando en ~0.03 se obtienen 4 clusters, y un 5to separando Abril de ASO por continuidad temporal. Confirma la validez del agrupamiento “a ojo”

An optimal (if somewhat arbitrary) division of the year can be seen in Figure X based on monthly mean values of each PC…

This division is supported by hierarchical clustering…

Notes:

Geopotential Fields

Lo anterior justifica el agrupamiento de los meses que viene.

Zonal anomaly of 200hPa geopotential field with zonal wavenumber 1 filtered out. Areas with zonal wind greater than 30 m/s are hatched.

Zonal anomaly of 200hPa geopotential field with zonal wavenumber 1 filtered out. Areas with zonal wind greater than 30 m/s are hatched.

Mean geopotential zonal anomaly with zonal wave 1 filtered out between 65°S and 35°S

Mean geopotential zonal anomaly with zonal wave 1 filtered out between 65°S and 35°S

Zonal anomaly of 200hPa geopotential field with zonal wavenumber 1 and 2 filtered out. Areas with stationary wave number less than 3 are shaded.

Zonal anomaly of 200hPa geopotential field with zonal wavenumber 1 and 2 filtered out. Areas with stationary wave number less than 3 are shaded.

Mean geopotential zonal anomaly with zonal wave 1 and 2 filtered out between 65°S and 35°S

Mean geopotential zonal anomaly with zonal wave 1 and 2 filtered out between 65°S and 35°S

Streamfunction

Mean streamfunction.

Mean streamfunction.

Mean streamfunction with zonal wave 1 filtered out.

Mean streamfunction with zonal wave 1 filtered out.

Mean streamfunction with waves 1 and 2 filtered out.

Mean streamfunction with waves 1 and 2 filtered out.

Fourier

Amplitude of zonal wave 3 for each season defined in the text.

Amplitude of zonal wave 3 for each season defined in the text.

Stationarity, seasonal mean monthly amplitude (MA) and amplitude of the seasonal mean (AM) zonal wave 3 for each season defined in the text.
season stationarity MA AM
DJFM 0.64 35.66 23.50
A 0.62 41.66 26.23
MJJ 0.52 45.22 23.90
ASO 0.54 44.14 24.04
N 0.20 37.18 6.69

Regressions

Regression between PCs and gh.

Regression between PCs and gh.

Regression between PCs and Psi.

Regression between PCs and Psi.

Regression of standarized PC with antarctic sea ice concentrations.

Regression of standarized PC with antarctic sea ice concentrations.

Regression of standarized PC with SST.

Regression of standarized PC with SST.

Correlation between ONI and each principal component
PC estimate p.value
PC1 -0.25 0.000000668
PC2 0.13 0.013721337
Regression between OLR and PCs

Regression between OLR and PCs

Regression between precipitation and PCs

Regression between precipitation and PCs

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